Don't you need to simply apply the max expected pressure?
Inventor only analyzes in the elastic range.
Can you attach your files(s) here?
You would need both a ramp up to Max positive pressure and then cycle down to Max negative pressure and return to static pressure.
I guess just two sim's, one Max Positive and the other Max Negative for a "quickie"
I do not know if heat will be a factor, as material strengths will change with temperature.
With all the bombings lately, maybe they should work in balistic and explosive features into FEA.
T.S.
The part I'm designing is a fireworks mortar.
I need to run the simulation to prove a point, that my new design is more efficent at launching a firework than traditional designs. Also, that it will better controll the explosive force in a a catastophic failure when compared to our compeditors design.
While your sugjestions here are valid, I forgot to mention that the explosive force is actually launching a projectile (the fireworks shell). This will dramaticly affect the forces being directed into the walls mortar for a split second as the pressure builds before ejecting the shell.
If I use the max power/min power trick, can I simply include a place holder in the mortar (for the shell) and let the simulation naturally eject it?
Or is the setup for this more complicated?
I don't think it will be that easy.
I am not sure if that is something you can start in dynamic simulation and export into FEA.
You may have to create the projectile and bond it to the tube, creating a pressure chamber for the analysis.
not true to world, but it might simulate the max condition per your needs.
T.S.
I tried a simple version, it did not move the projectile.
and pressure on the side walls of the tube is extended across the entire face of the tube, there is no division where the projectile seals the bore, so the analysis will run right past the projectile, exerting pressure evenly on the whole bore tube.
unless of course you split the faces of the tube, or bond the projectile to create the simulated pressure chamber, then assign pressure force to all faces in the chamber.
T.S.
Appoligies.
FEA is Finite Element Analysis AKA (stress analysis)
Inventor Ribbon Tab under Environments
When I referred to exporting to FEA I was refering to the scenerio below.
In Inventor you can create a dynamic simulation, adding movement, accelerations, momentum etc..
The dynamic simulator can then export the forces to the stress analysis system at a particular point in the simulation timeline, giving you all the forces at that exact moment in the system.
T.S.
Rusty
I'm coming from a background in 3D Studio MAX. If I where to simulate these interactions I would place the "force generator" in a position where the initial lift charge would be, then place the shell into the tube on top of that.
I would tell the program that the shell can't intersect the tube and that the "force generator" should apply force to the tube and the shell.
At that point the physics simulation would have no choice but to "launch" the shell because it's the only moveable part in the simulation.
I would assume that I could do the same in inventor ... does inventor have a setting for "world physics" where it's just generating gravity and physical interactions with all objects in a scene (or assembly)? Or do you need to set mechanical type constraints on everything?
@Anonymous wrote:I'm coming from a background in 3D Studio MAX. If I where to simulate these interactions I would place the "force generator" in a position where the initial lift charge would be, then place the shell into the tube on top of that.
I would tell the program that the shell can't intersect the tube and that the "force generator" should apply force to the tube and the shell.
At that point the physics simulation would have no choice but to "launch" the shell because it's the only moveable part in the simulation.
I would assume that I could do the same in inventor ... does inventor have a setting for "world physics" where it's just generating gravity and physical interactions with all objects in a scene (or assembly)? Or do you need to set mechanical type constraints on everything?
Doesn't work the same way.
Rusty
How does inventor apply force? Do you have to apply it to a spesific point? Or face?
Or can you setup a sort of "omni" force where the force is radiated from a point in space?
Go to Environments>Dynamic Simulation and a tutorial message should pop up.
This is an advanced topic and deserves (requires?) advanced training.
You might also obtain book by Wasim Younis>
The end question remains, is Inventor really the proper tool.
You can simulate you projectile, but.....
Rusty
Loads apply to faces.
If you need a load in one small spot on a face, you either need to model the component applying the load, and use that object to apply the load, or you can split the face with a sketch, and apply the load to the split off portion of the face.
I don't think inventor can model the type of load you are after, you will have to simulate it.
Kinda like simulating light bounces in the old 3d studio before radiocity, by creating lights that represented the light reflecting off of other surfaces, you could simulate radiocity before it was part of the renderer. So it may be possible to fake, but as stated above, the results will probably be innacurate unless you find a really clever way to do it.
T.S.
maybe you could build a tube in your shop, and explode it. see where it failed, and try to reproduce it in inventor.
@Anonymous wrote:
If I can't come up with a digital solution, that I will resort to prototyping and destructive testing.
Even with the right software tool, I don't think it is easy to set up a valid simulation. You would definately want to verify the digital "solution" with physical testing. What is the risk of being wrong....